Removal of poly finish ?

Construction and repair of Classical Guitar and related instruments
MarkInLA
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Joined: Mon Oct 11, 2010 2:43 am

Re: Removal of poly finish ?

Post by MarkInLA » Tue Jun 20, 2017 1:52 am

Catire, sorry for belated thank you. I've been over in jazz guitar for a long time now and just saw this today 6/19/17..I never did the refinish... Mark

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Philipp Lerche
Amateur luthier
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Location: Germany

Re: Removal of poly finish ?

Post by Philipp Lerche » Mon Jul 17, 2017 7:04 pm

A bit off but....

Why don't we just (natural) oil high grade luthier guitars ? I mean nobody will ever carry a 3000$ guitar to a camp fire.
It will just get dirty or stainy over time like the player himself. Also it is easy to clean/sand and re-oil it from time to time.

My stubborn grandpa always used oil and wax for his lutes and nothing could make him do it different. :)
"If you spend too much time thinking about a thing, you'll never get it done."
Bruce Lee

Best regards
Phil

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attila57
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Location: Budapest, Hungary

Re: Removal of poly finish ?

Post by attila57 » Tue Aug 01, 2017 10:09 pm

MarkInLA wrote:
Tue Jun 20, 2017 1:52 am
Catire, sorry for belated thank you. I've been over in jazz guitar for a long time now and just saw this today 6/19/17..I never did the refinish... Mark
I always use a hot air gun to remove poly finish. It softens and peels off nicely.
Music to hear, why hear'st thou music sadly?
Sweets with sweets war not, joy delights in joy...

William Shakespeare, Sonnet 8

MarkInLA
Posts: 1252
Joined: Mon Oct 11, 2010 2:43 am

Re: Removal of poly finish ?

Post by MarkInLA » Wed Aug 02, 2017 11:36 pm

Thanks for updates. I no longer am pursuing the refinish. I'm glad I didn't as I was just about to post something about My Cordoba C10 today !! But I do want to say: I wonder if a hot air gun could potentially loosen the glue at bridge or purfling ...M

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attila57
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Location: Budapest, Hungary

Re: Removal of poly finish ?

Post by attila57 » Tue Aug 08, 2017 8:53 pm

Use it with care... It is an art and a gun with a thermoregulator comes handy.
Music to hear, why hear'st thou music sadly?
Sweets with sweets war not, joy delights in joy...

William Shakespeare, Sonnet 8

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attila57
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Location: Budapest, Hungary

Re: Removal of poly finish ?

Post by attila57 » Wed Aug 30, 2017 8:30 pm

Just another addition: After an extended research over the different guitar and woodworkers' forums it seems to me that a heat gun is definitely the first choice for removing a polyester finish, but for polyurethane a scraper and sandpaper are the best option.

How can you tell the difference? The polyester finish bubbles with moderate heat and peels off in large flakes easily. It is usually slightly orange-coloured, so it alters the natural colour of the wood.

The polyurethane finish is crystal clear and without any colour when fresh, but easily gets opaque (white) when it gets older, especially in a thicker layer. It doesn't peel off with heat, but burns into the wood if it is exposed to heat.
Music to hear, why hear'st thou music sadly?
Sweets with sweets war not, joy delights in joy...

William Shakespeare, Sonnet 8

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